This invention reltes to shock absorbers and, more particularly, to hydraulic shock absorbers having novel fluid flow circulating and metering means.
Generally, hydraulic shock absorbers provide a restricted orifice for the passage of hydraulic fluid therein from one side of a piston to the other side thereof to retard or dampen the movement of the piston and thereby the relative movement of the parts to which the opposite ends of the shock absorber are attached. Heat is generated in the hydraulic fluid as a result of the consequent pressure drop and increased velocity of the fluid flowing through the restricted orifice from the high pressure side of the piston to the low pressure side thereof. This heat generation is intensified under rapid and repeated cycling of the piston and can pose problems including premature failure of the sealing rings and/or other components of the shock absorber, requiring frequent repair or replacement.
Also, it is sometimes desirable to increase or decrease the rate of fluid flow from one side of the shock absorber piston to the other side thereof for the purpose of adjusting the rate of deceleration of the load applied. To do this with conventional shock absorbers requires access into the internal structure thereof for adjusting or replacing the orifice structure. Not only is this time consuming and expensive, but also exposes the internal structure to contamination, as by particulates and other foreign matter.